Solenoid valve

ABSTRACT

A solenoid-operated valve intended primarily to exert a force closely proportional to energizing current and particularly adapted for use in fluid pressure and flow controlling systems. The device includes an annular housing of magnetic material enclosing a nonmagnetic bobbin on which a coil is wound. An armature reciprocable within the bobbin in proximity to a pole piece of the housing exerts a force on a ball which seats at the end of an axial bore extending through the pole piece. The controlled fluid may communicate with the interior of the bobbin; one end of the bobbin is closed and the other end is sealed to the housing so that the fluid may not escape from the device. The fluid circuit through the valve is completed through holes in the pole piece.

United States Patent [191 Knape SOLENOID VALVE [75] Inventor: Richard S.Knape, Grand Rapids,

Mich.

[73] Assignee: General Motors Corp., Detroit,

Mich.

[22] Filed: Oct. 9, 1973 21 Appl. No.: 404,255

[52] US. Cl. 251/139, 251/129 [51] Int. Cl F16k 31/06 [58] Field ofSearch 251/129, 139

[56] References Cited UNITED STATES PATENTS 3,225,782 12/1965 Begley etal. 251/139 X 3,470,892 10/1969 Barker 137/4875 X 3,529,620 9/1970Leiber 251/139 X 3,796,409 3/1974 Burckhardt 251/139 FOREIGN PATENTS ORAPPLICATIONS 740,225 11/1955 Great Britain 137/625.64

[111 3,861,644 Jan. 21, 1975 Primary ExaminerArnold Rosenthal Attorney,Agent, or Firm-Paul Fitzpatrick [57] ABSTRACT A solenoid-operated valveintended primarily to exert a force closely proportional to energizingcurrent and particularly adapted for use in fluid pressure and'flow.

controlling systems. The device includes an annular housing ofmagnetic'material enclosing a nonmagnetic bobbin on which a coil iswound. An armature reciprocable within the bobbin in proximity to a polepiece of the housing exerts a force on a ball which seats at the end ofan axial bore extending through the pole piece. The controlled fluid maycommunicate with the interior of the bobbin; one end of the bobbin isclosed and the other end is sealed to the housing so that the fluid maynot escape from the device. The fluid circuit through the valve iscompleted through holes in the pole piece.

3 Claims, 2 Drawing Figures SOLENOID VALVE My invention is directed toelectromagnetic valves which are intended to exert a closing orpressureresisting force which is a function, preferably a substantiallylinear function, of the energization of a coil or solenoid which is apart of the device. Valves according to my invention are particularlyadapted for use in engine controlling systems and in general in systemsin which the force exerted may be a means for providing an interfacebetween an electrical control system and a fluid flow or pressureregulating system. Solenoid devices according to my invention are ofstructure which is particularly adapted to leakproof operation, tolinearity of response, to economical fabrication and compact dimensions,and to convenient association with valve bodies and the like.

My invention provides in some respects an improvement on that describedin Deckard U.S. Pat. application Ser. No. 327,958 filed Jan. 30, 1973[U.S. Pat. No. 3,805,203]. It represents a structure more adapted tolarge-scale production and use, and may serve the same fluid-controllingfunction as the Deckard device. It is more completely self-contained.

Generally speaking, in its preferred embodiment, the valve comprises acup-shaped housing having an annular pole piece closing one end of thehousing, and having a bobbin mounted within the housing defining a guidefor an armature reciprocable within the bobbin. The armature isattracted to the pole piece upon energization of a solenoid wound aroundthe bobbin. The fluid may be displaced past the armature in case of itsmovement, and the bobbin is sealed to the pole piece to contain fluidwithin the enclosure defined by the bobbin. The armature biases aspherical valve member which cooperates with a seat at the end of a boreextending through the pole piece.

The nature of my invention and its advantages will be more fullyapparent from the succeeding detailed description of preferredembodiments of the invention and the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a valve device embodying theinvention as installed.

FIG. 2 is a sectional view taken on the plane indicated by the line 2-2in FIG. 1.

Referring first to FIG. 1, the electromagnetic valve device 1 comprisesa cup-shaped housing 2 defining a generally cylindrical internal chamber3 recessed as indicated at 4 at the open end of the housing. An annularpole piece 6 fitted in the recess 4 substantially closes the open end ofthe housing. The pole piece includes an external boss 7 and an internalboss or pole 8 extending into the housing along its axis. The housingand pole piece are made of a suitable magnetic material, preferably SAEtype 1020 steel. The solenoid or coil 10 which generates the magneticforce is wound on a bobbin or spool 11 made of a suitable nonmagneticmaterial. The preferred material is an aluminum alloy identified as SAE606l-T6. The bobbin includes a flange 12 which abuts the inner surfaceof the pole piece 6 and is impinged between it and a shoulder 14 at thebottom of recess 4. It includes a central hollow cylindrical portion 15and a second flange 16.

The cylindrical portion defines internally a guideway for a magneticreciprocable armature 18, also preferably of SAE 1020 steel. The end ofthe bobbin remote from pole piece 6 extends into and is located radiallyby a bore 19 in the closed end of the housing. This end of the bobbin isclosed by an integral wall 20. The portion of the bobbin adjacent thepole piece 6 extends over the pole 8 with radial clearance. The bobbinis located radially by its piloted fit of flange 12 in the housing andof cylindrical portion 15 with the interior of bore 19, and is locatedaxially between the pole piece 6 and the housing 2.

The armature 18 is approximately of cylindrical shape, with a concaveconical forward end 22 which is disposed adjacent to a correspondingconical nose 23 on the pole, the device defining an air gap between thesurfaces of portions 22 and 23. Armature 18 is recessed to receive aspherical valve member 25 which may engage a seat 26 at the inner end ofa bore 27 along the axis of the pole piece 6. Preferably, the armaturehas two shallow flanges 28 and 29 which bear against the interior of thebobbin cylinder 15. These flanges are partially cut away to define flatsor slots indicated at 31 and 32 to permit fluidto flow freely past thearmature when it moves. The fluid may enter the device through the bore27 and till the space around the armature. It is prevented from leakingby a gasket or sealant 33 disposed between the forward face of thebobbin and the pole piece. It is essential to fast transientdisplacement response that no significant fluid pressure differential begenerated by shifts of the armature. If slow movement is acceptable,some fluid damping of armature movement by fluid in the cylinder 15 maybe desirable.

The coil 10 would on bobbin 11 is enclosed by a coating 34 of epoxyresin. Electrical lead-in wires 36 extend through an opening 38 in thehousing 2.

As will be understood, if magnetizing current is passed through leads 36to the solenoid 10, the resulting magnetic flux flows through thehousing 2, armature 18, and pole piece 6, and tends to draw the armatureto the right, as illustrated, into contact with the pole piece. For anygiven position of the armature, the force exerted is substantiallyproportional to the magnetomotive force, which again is substantiallyproportional to current as long as the saturation of the iron does notsignificantly vary the reluctance of the magnetic circuit. If thearmature moves, the force increases as the surfaces 22 and 23 approacheach other.

The device is intended primarily, however, for use in a substantiallystationary condition in which force is modulated rather than position.This modulation may be accomplished by varying the magnitude of aconstant current or by varying the average current as, for example, byduty cycle control of current flowing through the solenoid.

The housing 2 is illustrated as mounted so that the pole piece 6 abuts abody or valve block 40 which defines a bore or passage 42 into which theexternal boss 7 of the pole piece is piloted. An O-ring 43 preventsleakage around the boss 7. The housing 2 has a flange 44 adjacent theblock 40 which is engaged by suitable clamping means (not illustrated)to hold the valve device in position on the block 40. Passage 42 thuscommunicates through bore 27 with valve 25, 26. Fluid which passesthrough the valve may discharge through the gap 24 between the armatureand the pole 8, between pole 8 and cylinder 15, and through holes 46 inthe web of pole piece 6 into a recess 48 in block 40 surrounding boss 7.This recess may discharge through a drain or other exit passage 50. Ifthis passage is under pressure, a gasket or other seal may be providedbetween the pole piece 6 and block 40 around recess 48.

As will be apparent, if fluid is introduced through the passage 42, theresistance to its escape will be a function of the force exerted by thearmature 18 and, therefore, the average current going through thesolenoid of the valve device may maintain the pressure communicatingwith the inlet 42 at a particular desired value as a function of thiscurrent. If the supply of fluid through passage 42 is limited, thisregulation may be accomplished with slight travel of valve member 25.The valve is thus well-adapted to regulate a pressure to control furtherhydraulic devices as a function of solenoid current.

The valve ball 25 may be of various materials. Both steel and firmrubber balls have worked successfully. The rubber tends to seal somewhatbetter.

Among the advantages of the valve device as illustrated herein are thesubstantially constant or consistent relation of force to current, afast response to transients, and negligible hysteresis; that is,variation of the force exerted between increasing and decreasing currentflows. It is self-contained, and mounts easily on a recessed opening ina valve block or other device to be controlled.

The particular devices illustrated are shown to scale and have a housingabout 1 /2 inches in diameter.

The detailed description of the preferred embodiment of the inventionfor the purpose of explaining the principles thereof is not to beconsidered as limiting or restricting the invention, since manymodifications may be made by the exercise of skill in the art.

I claim:

1. An electromagnetic valve device comprising, in combination, ahousing; a pole piece abutting the housing including a first hollow bossextending into the housing and a second hollow boss extending from thehousing; an annular bobbin fixed in the housing; a solenoid on thebobbin; an armature reciprocably guided within the bobbin, the armatureand the first boss having confronting portions defining an air gap;means providing a fluid seal between the bobbin and the pole piece; thehousing, pole piece, and armature being of a magnetic material and thebobbin being nonmagnetic; the bosses defining a fluid inlet passageterminating in an annular seat at the inner end of the first boss; and amovable valve closure member disposed adjacent the seat and biasableagainst the seat by energization of the solenoid; a fluid outlet passageextending along the exterior of the first boss bounded by the first bossand the bobbin; the pole piece defining an outlet from the outletpassage.

2. An electromagnetic valve device comprising, in combination, ahousing; a pole piece abutting the housing including a first hollow bossextending into the housing and a second hollow boss extending from thehousing; an annular bobbin fixed in the housing; a solenoid on thebobbin; an armature reciprocably guided within the bobbin; the armatureand the first boss having confronting portions defining an air gap; andmeans providing a fluid seal between one end of the bobbin and the polepiece; means closing the other end of the bobbin; the armature havingsufficient clearance from the pole piece and bobbin for displacement offluid upon reciprocation thereof; the housing, pole piece, and armaturebeing ofa magnetic material and the bobbin being nonmagnetic; the bossesdefining a fluid inlet passage terminating in an annular seat at theinner end of the first boss; and a movable spherical valve closuremember disposed adjacent the seat between the armature and first bossand biasable against the seat by energization of the solenoid; a fluidoutlet passage extending along the exterior of the first boss bounded bythe first boss and the bobbin; the pole piece defining an outlet fromthe outlet passage.

3. An electromagnetic valve device comprising, in combination, ahousing; a pole piece abutting the housing including a first hollow bossextending into the housing and a second hollow boss extending from thehousing; an annular bobbin in the housing piloted at the end of thebobbin adjacent the pole piece on the housing, the bobbin including aportion providing a pilot connection between the other end of the bobbinand the housing; means closing the said other end of the bobbin againstescape of fluid; a solenoid on the bobbin; an armature reciprocablyguided within the bobbin, the armature and the first boss havingconfronting portions defining an air gap; means providing a fluid sealbetween the bobbin and the pole piece; the armature having sufficientclearance from the pole piece and bobbin for flow of fluid uponreciprocation thereof; the housing, pole piece, and armature being of amagnetic material and the bobbin being nonmagnetic; the bosses defininga fluid inlet passage terminating in an annular seat at the inner end ofthe first boss; and a movable valve closure member disposed adjacent theseat and biasable against the seat by energization of the solenoid; afluid outlet passage extending along the exterior of the first bossbounded by the first boss and the bobbin; the pole piece defining anoutlet from the outlet passage.

1. An electromagnetic valve device comprising, in combination, a housing; a pole piece abutting the housing including a first hollow boss extending into the housing and a second hollow boss extending from the housing; an annular bobbin fixed in the housing; a solenoid on the bobbin; an armature reciprocably guided within the bobbin, the armature and the first boss having confronting portions defining an air gap; means providing a fluid seal between the bobbin and the pole piece; the housing, pole piece, and armature being of a magnetic material and the bobbin being non-magnetic; the bosses defining a fluid inlet passage terminating in an annular seat at the inner end of the first boss; and a movable valve closure member disposed adjacent the seat and biasable against the seat by energization of the solenoid; a fluid outlet passage extending along the exterior of the first boss bounded by the first boss and the bobbin; the pole piece defining an outlet from the outlet passage.
 2. An electromagnetic valve device comprising, in combination, a housing; a pole piece abutting the housing including a first hollow boss extending into the housing and a second hollow boss extending from the housing; an annular bobbin fixed in the housing; a solenoid on the bobbin; an armature reciprocably guided within the bobbin; the armature and the first boss having confronting portions defining an air gap; and means providing a fluid seal between one end of the bobbin and the pole piece; means closing the other end of the bobbin; the armature having sufficient clearance from the pole piece and bobbin for displacement of fluid upon reciprocation thereof; the housing, pole piece, and armature being of a magnetic material and the bobbin being nonmagnetic; the bosses defining a fluid inlet passage terminating in an annular seat at the inner end of the first boss; and a movable spherical valve closure member disposed adjacent the seat between the armature and first boss and biasable against the seat by energization of the solenoid; a fluid outlet passage extending along the exterior of the first boss bounded by the first boss anD the bobbin; the pole piece defining an outlet from the outlet passage.
 3. An electromagnetic valve device comprising, in combination, a housing; a pole piece abutting the housing including a first hollow boss extending into the housing and a second hollow boss extending from the housing; an annular bobbin in the housing piloted at the end of the bobbin adjacent the pole piece on the housing, the bobbin including a portion providing a pilot connection between the other end of the bobbin and the housing; means closing the said other end of the bobbin against escape of fluid; a solenoid on the bobbin; an armature reciprocably guided within the bobbin, the armature and the first boss having confronting portions defining an air gap; means providing a fluid seal between the bobbin and the pole piece; the armature having sufficient clearance from the pole piece and bobbin for flow of fluid upon reciprocation thereof; the housing, pole piece, and armature being of a magnetic material and the bobbin being nonmagnetic; the bosses defining a fluid inlet passage terminating in an annular seat at the inner end of the first boss; and a movable valve closure member disposed adjacent the seat and biasable against the seat by energization of the solenoid; a fluid outlet passage extending along the exterior of the first boss bounded by the first boss and the bobbin; the pole piece defining an outlet from the outlet passage. 